What sense does it make to have expensive health insurance plus supplemental health insurance (as if your health was important to you), but then smoke 2 packs a day? Do you have insurance so you can smoke 2 packs a day? Better off not smoking and having basic coverage.
based on the black and white logic you present in your last sentence, i take it you have never dealt with addiction.
Addiction is horrible. It is pernicious and can be debilitating. It makes you feel like you have no control. Addicts benefit from intervention and therapy, and they would benefit from having insurance that covers those things too.
Addictions can deteriorate your health. Some quickly, some slowly. On a theoretical level, you'd be better off not being an addict than having to rely on insurance to restore your health.
Many addictions have a significant behavioral aspect. Learning (or relearning!) that you are in control of your behaviors and that you make the choice to act in your own best interest is surprisingly difficult. Nobody can do that for you; you have to do that yourself.
Once you gain that level of self control and self awareness, the addiction can be more easily managed. If you need cognitive behavioral therapy in order to make those gains, then you should probably make sure you get the right kind of coverage for that. You can, essentially, do CBT on your own, but it takes determination and will.
FWIW, the word "Better" indicates a comparative or relative relationship, not a black-and-white one.